Endoscopes are commonly used to view the interior passage of an object. An endoscope typically includes an endoscope body and optical components carried by the endoscope body to enable viewing of the passage distally of the distal end of the endoscope body and within a field of view of the endoscope. The optical components may include, for example, illumination and visualization fibers in the endoscope body for conducting light distally and an image proximally, of the endoscope body.
Endoscopes have industrial applications wherein the endoscope can be used to view a passage within, for example, industrial equipment. Endoscopes also have medical applications wherein the endoscope is used to view a passage within the body of a patient.
Medical endoscopes used for angioscopy are commonly placed in the vascular system using a guidewire. For example, the guidewire may first be placed within a blood vessel and the endoscope may have a lumen receiving the guidewire such that the endoscope can be moved along the guidewire to a desired position. It is also known to provide an angioplasty catheter, as opposed to an endoscope, with a fixed guidewire which allows the operator to track and place the catheter at the desired location in the vascular system.
One problem with these procedures is that it may be difficult to view curved, collapsed or partially collapsed portions of the passage. In addition, material within the passage may tend to obstruct viewing through the endoscope within the field of view of the endoscope.
In an effort to solve this problem, it is known to use a resectoscope for removing or ablating unwanted tissue. It is also known to use a nozzle in an attempt to spray material off the distal lens of the endoscope as shown, for example in Auhll et al U.S. Pat. No. 5,207,213. However, these techniques do not address the visualization problems posed by a curved, collapsed or partially collapsed passage and resection increases the likelihood of injury and trauma to the patient. Similarly, the use of a technique as shown for example in Hiltebrandt U.S. Pat. No. 4,682,585 for radially spacing the distal objective of the endoscope is also not effective to address these problems.
Endoscopes have also been introduced through hollow sleeves with sharpened points for puncturing the abdomen in laparoscopic procedures such as shown in Hiltebrandt U.S. Pat. No. 4,345,589 and Yoon U.S. Pat. No. 4,254,762. However, the rigidity of the hollow sleeves and their sharp tips make them unsuited for many procedures where tissue penetration is to be avoided and for passages which are curved.